Earth boring tool



United States Patent [72] Inventor Carl P. Aarup FOREIGN PATENTS Sprlnxfkld, 183,697 11/1955 Austria 166/50 1 pp Nor 769,086 512,715 11/1930 Germany... 175/422 [221 Filed Oct-21,1968 DI5,605 9/1956 Germany 166/50 [45] Patented Oct. 27, 1970 I [73] Assignee Brite-Llte Enterprises Inc. Primary Exammer- David Brown S i fi ld Ill AttorneyJohnson, Dienner, Emrich, Verbeck & Wagner a corporation of Delaware ABSTRACT: A tool for use with a tubular conduit to assist in the insertion of the conduit through earth or similar substance, [54] EARTH BORING TOOL including a body having a generally cylindrical rearward por- 5 Claims 4Drawing Figs. tion and a conically shaped forward end portion. The rearward cylindrical portion is adapted to be releasably secured to [52] US. Cl 175/422, an end of the conduit A longitudinally extending flow 175/21 chamber is formed in the body in communicating relation with [5]] Int. Cl EZlb 7/18, the real-ward end thereof and a primary axial flow passage is 19/00 disposed to communicate with the flow chamber and the apex [50] Field ofSearch 175/422, f the conical end f the body. A plurality of Secondary flow 21; 166/50 passages intersect the conical peripheral surface of the body R r d and the flow chamber with their axes forming acute angles [56] e erences e with the axis of the primary axial flow passage such that water UNITED STATES PATENTS introduced into the flow chamber is discharged through the 862,972 8/1907 Jones 175/422 axial and secondary flow passages to effect erosion of earth 1,994,884 3/1935 Chew l75/422X forwardly of the boring tool whereby the conduit may be 2,137,261 I l/l938 Boll et al l75/67X moved longitudinally through the earth.

4 15 20 16 r r. rm. ruga as)" I "I I I 1 l AW\ .C. s 9 v v v v ,215 :1) J0 2 l EARTH aonmc TOOL BACKGROUND OF THE INVENTION In installing tubular conduits for carrying hydraulic fluids or shielding electrical conductors underground, it is conventional to dig a trench or channel, lay the conduit within the trench, and fill the trench with the earth removed therefrom to bury the conduit below the surface of the earth. When confronted with a concrete sidewalk, driveway, shrubbery or other obstruction, digging a tunnel under the obstruction for inserting of the conduit is difficult and time consuming. There are at present commercially available hydraulic and mechanical jacks for forcing or driving pipes and conduits through the earth underlying sidewalks and like obstructions, but such jack devices are bulky and expensive.

Attempts have been made to effect the insertion of conduits beneath sidewalks and like obstructions through securing tip devices to the forward ends of the conduits and passing hydraulic fluids such as water through the conduits and discharging the fluids outwardly from the tip devices. Generally, the tip devices have outwardly projecting cutting blades or cutting tips and the conduit is actuated simultaneously with the ejection of water outwardly from the tip device such that the cutting blades cut or drill the earth as the conduit is moved longitudinally. These tip devices require continued sharpening and are insufficient for their intended purpose.

SUMMARY OF THE INVENTION The present invention relates generally to earth boring tools, and more particularly to such a tool having fluid flow passages selectively disposed therein and adapted to be connected to a conduit through which liquid under pressure is passed for discharge from the flow passages.

In carrying out my invention. I provide an earth boring tool including a body having a generally cylindrical rearward portion adapted to be releasably secured to an end of a tubular conduit, and a forward conically shaped end. A longitudinally extending flow chamber is provided in the body which communicates with the end of the body secured to the conduit. A primary axial flow passage intersects the apex of the conically shaped end and the flow chamber with a plurality of secondary flow passages being formed in the body such that they intersect the peripheral conical surface and the flow chamber. The

secondary flow passages are of equal cross-sectional area and the primary flow passages as a cross-sectional area equal to the total cross-sectional areas of the secondary flow passages. The axes of the secondary flow passages intersect the conical surface of the body generally intermediate the length and form selected acute angles with the longitudinal axis of the primary passage. The rearward end portion of the body has an annular curved trailing edge to assist in rearward movement of the boring tool during operation.

My invention and the manner of operation thereof may best be understood by reference to the following description taken in connection with the accompanying drawing in the several FIGS. of which like reference numerals identify like elements.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a vertical sectional view illustrating an earth boring tool in accordance with the present invention secured to the forward end of a conduit being installed beneath a sidewalk obstruction;

FIG. 2 is an elevational view of the earth boring tool illustrated in FIG. I,

FIG. 3 is an end view looking from the left in FIG. 2; and

FIG. 4 is a longitudinal sectional view taken substantially along the line 4-4 of FIG. 2 looking in the direction of the arrows. 1

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawing, and in particular to FIG. 1, an earth boring tool, indicated generally at 10, is illustrated as being secured on the forward end of a length of conduit comprising a tubular pipe 12. The conduit or pipe 12 is shown being installed under an obstruction 14 such as a concrete sidewalk, driveway, shrubbery or other like obstruction which cannot be readily removed for digging a trench in which the conduit is to be laid. As will be more fully described hereinbelow, the earth boring tool 10 when used in conjunction with the length of conduit 12 and a length of flexible liquid supply hose l6 permits the conduit to be readily inserted through the earth 18 underlying the obstruction 14 without having to move or otherwise adjust the obstruction.

When installing a conduit 12 with the earth boring 10, a trench or ditch into which portions of the conduit 12 on opposite sides of the obstruction are to be laid is dug to positions adjacent either side of the obstruction 14 as shown at 20. The earth boring tool 10 is thereafter attached to the forward end of the conduit 12 and the flexible hose 16 is secured to the rearward end of the conduit in a conventional manner as through a threaded coupling 22. The conduit 12 is then positioned at the depth at which it is desired to lay the conduit and hydraulic fluid such as water is introduced into the conduit 16 under pressure to start the installing operation as described below.

Referring now to FIGS. 2-4, the earth boring tool 10 comprises a body member, indicated generally at 24, having a first or rearward generally cylindrical end portion 26 adapted to be releasably secured to an end of the flow conduit 12. For this purpose, the end portion 26 has a conventional internal thread 28 adapted to receive a corresponding threaded end portion of the conduit 12 in threaded engagement therewith. The cylindrical end portion 26 of the body 24 has an annular curved trailing edge surface 30 formed between the cylindrical peripheral surface and a rear end surface 32 of the body. The trailing edge 30 may comprise a turned radius and permits the boring tool to be readily moved rearwardly during operation as will become apparent hercinbelow.

The body 24 of the earth boring tool 19 has a generally conically shaped second or forward end portion 34 having its longitudinal axis coincident with the longitudinal axis of the cylindrical end portion 26. The taper or included angle alpha of the conically shaped forward end portion 34 is between about 15 to 30 degrees, it having been found that the earth boring tool provides optimum performance when the included angle is 15 degrees.

A generally cylindrical flow chamber 36 is formed in the body 24 of the earth boring tool 10 and extends along the longitudinal axis thereof forwardly of the threaded portion 28. The longitudinal length or extent of the flow chamber 36 is limited such that the wall thickness of the forward conical portion 34 of the body adjacent the forward end of the chamber 36 will have sufficient wall strength.

The body 24 has a primary flow passage 38 disposed axially within the body in communicating relation with the flow chamber 36 and intersects the apex or forwardmost end 40 of the conically shaped second end 34. The forwardmost end 40 of the conically shaped end portion 34is preferably formed in a manner to strengthen the wall of the body adjacent the forward end of the flow passage 38.

Noting FIG. 3, taken in conjunction with FIG. 4, the body 24 of the earth boring tool 10 includes a plurality of secondary flow passages 42 which intersect the peripheral surface of the conically shaped second end portion 34 and the flow chamber 36, thereby providing communication between the conical surface and the opening in the cylindrical end portion 26 defined by the threaded portion 28. It has been found that while the earth boring tool 10 will operate satisfactorily with two secondary flow passages 42, the performance is improved utilizing three and preferably four secondary flow passages.

The use of four secondary flow passages 42 intersecting the peripheral surface of the conically shaped portion 34 in equidistant circumferentially spaced relation thereabout as shown in FIGS. 3 and 4 provides improved directional control during usage of the tool. The secondary flow passages 42 are disposed within the body 24 that they intersect the peripheral surface of the conical forward end portion 34 at points generally halfthe length of the flow areas, considered in planes transverse to the axes of the respective secondary flow passages. The cross-sectional flow' areas of the secondary flow passage ,42 are established such that the total cross-sectional area of the secondary flow passages is about equal to the cross-sectional area of the axial flow passage 38, considered in a plane transverse to the axis of the primary flow passage. The cross-sectional area of the cylindrical flow chamber36 is made at least equal to the-combined or total cross-sectional area of the primary flow passage 38 and the secondary flow passages 42.

It has been found that an earth boring tool in accordance with the present invention when used with 1%,56, or 1' inch diameter pipes provides optimumoperation when the primary flow passage 38 has a diameter of between about three thirtyseconds and five thirty-seconds of an inch and the secondary flow passages 42 have diameters of between about three sixtyfourths and five sixty-fourths of an inch. The flow areas of the primary and secondary flow'passages 38 and 42, respectively,

' may be varied somewhat dependent upon the pressure of the' liquid or hydraulic fluid introduced into the flow chamber 36, with smaller diameter flow passages being provided when a limited or lower pressure source is available.

Having described the earth boring tool 10, its operation will now be briefly described. After digging thetrench or ditch 20 on either side of the obstruction to a depth at least equal to, the depth at which it is desired to lay the conduit 12, the earth boring tool 10 is'threadedly secured to the forward end of the conduit and the flexible hose 16 is secured to the rearward end thereof. A hydraulic fluid under pressure, such as water from a pump or other suitable source, is then introduced into the hosel6 whereupon it is discharged in the form of jets through the primary and secondary flow passages 38 and 42, respecof the earth boring-tool 10 such end of the conduit being disposed to allow-removal of the boring-tool 10. The forward end of conduit 12 is then ready to have other conduit segments or lengths secured thereto in the r trench 20.

' The earth boring tool 10 has been found to provide an inexpensive apparatus which may be readily carried from job to 7 surface, said bod job and eliminates the heretofore required heavy and expensive equipment necessary to effect the laying of pipe or conduits beneath obstructions.

While a preferred embodiment of my invention has been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made therein without departing from the invention in its broader aspects.

I claim:

l 1. An earth boring tool for use with a fluid flow conduit and the like, comprising, a body member having a first generally cylindrical end portion adapted to be releasably secured to an endof the flow conduit and having an annular curved trailing member having a generally conically shaped second en portion contiguous to said cylindrical portion, an axially disposed primary flow passage communicating between said first end portion and the apex of said conically shaped second end portion, and a plurality of elongated secon dary flow passages of equal cross-sectional area comrn'unicab ing with the peripheral surface of said conically shaped second end portion and said primary flow passage, the axes of said secondary flow passages forming included angles of between 5 to 30 with the axis of said primary flow passage, said primary flow passage having a cross-sectional flow area approximately equal to the total cross-sectional flow areas of said secondary orifices such that fluid introduced into the fluid flow conduit is discharged through said primary and secondary flow passages.

2. An earth boring tool as defined in claim 1 wherein said body includes a flow chamber therein communicating with said first end and said primary and secondary flow passages, said flow chamber having a transverse cross-sectional area at least equal to the total transverse cross-sectional areas of said primary and secondary flow passages.

tively, in the tool body 24. The discharging jets of water act against the earth 18 adjacent the forward conical surface 34 of the tool body and erodethe earth with the earth'particles being carried rearwardly along the tool body suspended in the discharged water. As the earth is eroded forwardly of the earth boring tool 10, the operator works the conduit 12 longitu- 3. An earth boring tool'as defined in claim I wherein diametrically opposed generally longitudinally extending surface elements of said conically shaped second end of said-body form an included angle therebetween of between about 15 to 30.

4. An'earth boring tool as defined in claim I wherein diametrically opposed surface elements of said conically shaped second end form an included angle of about 15 th'erebetween, considered in a plane containing the longitudinal axis of said body, and the axes of'said secondary flow passages form included angles of about 5 with the axis of said primary flow passage.

'5. An earth boring tool as defined in claim 1 wherein said body member has four secondary'flow passages intersecting the peripheral surface of said conically shaped second end portion in equidistant circumferentially spaced relation. 

